Two-temperature refrigerating system



3 1947- E. F. HUBACKER 2,4233% TWO-TEMPERATURE REFRIGERATING SYSTEM Filed Feb. 21, 1944 F-Huczcver Patented duty 3, 1%47 UNITED STATES PATENT TWO-TEMPERATURE REFRIGERATING SYSTEM Earl F. Hubacker, Highland Park,

to Borg-Warner Corporation,

corporation of Illinois Application February 21, 1944, Serial No. 523,280

6 Claims.

Also it is a principal object of this invention to provide, in a multi-stage refrigerating system, an arrangement wherein a high-pressure vapor from a high-temperature evaporator is returned to a compressor that is common to a low-temperature evaporator, the said evaporators being individual to the respective refrigerating compartments wherein different temperatures are maintained.

' In this connection it is a further object hereof to provide a two-suction rotary compressor assembly wherein the high-pressure suction inlet from a high temperature evaporator is maintained at a higher pressure than the low-pressure suction inlet from the low-temperature evaporator.

Still another object of this invention is to provide a refrigerating system of the character herein contemplated wherein a capillary tube is interposed in the line between a condenser and a hightemperature evaporator, such capillary tube adapted to perform the function ofa choke coil to effect a constant throttle upon the fluid.

A further object hereof resides in, providing a capillary member or choke tube coil between the high and low temperature evaporators of a refrigerating system to effectively meterv the fluid as it flows between the respective evaporators.

A still further object of this invention is to provid simple metering means in the respective high-pressure and low piessure conduits to control the flow of refrigerant to the respective hightemperature and low-temperature evaporators, such metering means comprising capillary tubes that are calibrated to the specific requirements of a particular installation as to the capacities of the respective refrigerating chambers or compartmentsr Additional objects, aims, and advantages of the invention contemplated herein will be apparent to persons skilled in the art after the construction and operation of the multi-temperature refrig- Mich, assignor Chicago, 111., a

crating system is understood from the within description.

It is preferred to accomplish the numerous objects of this invention and to practice the same in substantially the manner hereinafter fully described and as more particularly pointed out in the appended claims, reference being made to the accompanying drawings that form a part of this specification, wherein:

Fig. 1 is a view in diagrammatic form showing the instrumentalities of this multi-temperature refrigerating system; and

Fig. 2 is a view, somewhat schematically drawn, of a unitary double-suction compressor such as utilized in the refrigerating system contemplated herein.

The drawings are to be understood as being more or less of a schematic character for the purpose of disclosing a typical or preferred embodiment of the improvements contemplated herein, and in these drawings like reference characters identify the same parts in the several views.

The multi-temperature refrigerating system contemplated herein preferably comprises two chambers or compartments shown in broken lines, A and B, in which different temperatures are to be maintained. The chamber B may be termed the so-called deep-freeze or "quick freeze lowtemperature compartment of a household refrigerator, while the other chamber A is the normal cold compartment wherein the temperature is higher than in the deep-freeze compartment B. Both of the chambers A and B, as well as the other instrumentalities of this refrigerating system shown in Fig. 1, are enclosed within the usual refrigerator cabinet which is not illustrated since it forms no portion of the present invention.

The refrigerating agent, preferably methylchloride (CH3C1) is raised to a high pressure in the compressor 5 from which it is discharged through the outlet port 6 into a pipe 1 that leads to a condenser coil 8 where the gas becomes liquified. The compressor 5 is a unitary double-suction arrangement of the rotary type to create high pressure upon the refrigerating agent for forcing it through the closed insulating conduits or lines that pass through the respective chambers or compartments A and B. The high-pressure suction line or return conduit 9 leads into the compressor through the high pressure suction port 10 to return refrigerant to the compressor from the high-temperature chamber A, and a low-pressure suction line or conduit ll leads into the compressor through the low-pressure suction port l2 to return refrigerant from the lowtemperature chamber 13 to the compressor. The porting arrangement of the unitary compressor is such that the low-pressure suction port 12 is open to the compressor cylinder at all times, while the high-pressure suction port I is opened only when the rotor has completed a portion or approximately 50% to 60% of its stroke and there-. after the refrigerantfrom the high-pressure suction line 9 will be admitted to the compressor.

cylinder during the remainder of the stroke of the rotor. The eifect of this arrangement is that the high-pressure suction inlet of the compressor is maintained at a higher pressure than the lowpressure suction inlet that receives the refrigerant returning from the low-temperature or deepfreeze chamber B.

Upon leaving the condenser 8 the liquified refrigerant passes through a, capillary member l3 that communicates at one end with said condenser and at its other end discharges into a high-temperature evaporator coil H within the chamber A that is to be maintained at a temperature above that in. thedeep-freeze chamber B. The capillary member l3 is'preferably a coiled tube having-a small internal diameter or borethatis calibrated to predetermined dimensions depending'upon the particular requirement for refrigerant in. the evaporator 14. The capillary member 13 acts as a choke tube coil to throttle the flowing refrigerant and meter the liquid to .the high-temperature evaporator in the quantity that is needed by the latter. Thls action is attributed to the wellknown phenomenon of physics which is associated with surface tension and angle of contact, an example of which is the rise of liquids in a wick or tube- The evaporator ll effects a vaporization of a portion of the liquid refrigerant and the vapor so, liberated is withdrawn from the evaporator 'into high-pressure suction line; 9 through which thiswithdrawn vapor is returned to the compressor 5, i

The liquid portion any similar to the high-pressure capillary member l3, and it provides a constant throttle upon the liquid refrigerant to meter its feed to the deep-freeze or low-temperature evaporator ll. 'The vaporized'refrigerant leaves the low-temperature evaporator through the low-pressure suction line orconduit H and is returned to the compressor through the low-pressure suction p rt l2.

' evaporators H and I! return to such compressor through their separate return lines, and the full charge of the compressed refrigerant is discharged to the condenser 8. There are two closed refrigerant circuits, and a compressor and condenser, common to both circuits provided. Also the refrigerant is metered to the respective high-temperature and low-temperature evaporators I4 and I! through capillary members I3 and I6 that are individual to the respective evaporators.

While this invention has been described in detail in its present preferred form or embodiment, it will be apparent to-persons skilled in the art, after understanding the improvements, that various changes and modifications may be made therein without departing from the spirit or scope thereof. It is aimed in the appended claims to cover all such changes and modifications.

I claim:

1. A two temperature refrigerating system comprising, in combination, a compressor, a condenser into which compressed refrigerant is discharged from said compressor, a first evaporator,

, a second evaporator, a refrigerant restrictor means connected to and disposed between said condenser and said first evaporator and having a passage of relatively small cross-section thereif the "refrigerant in the high-temperature evaporator I that remains 'after the vapor has left said evaporator is dis- Check-valves or similar devices are provided in both suction return lines. A check valve l8 is interposed in the low-pressure suction return pipe II and it is placed close to the compressor or cylinder to reduce re-expansion volume to a minimum. Inthe high-pressure suction return "pipe 9a checlvalve i9 is located at a convenient V place'ftopreventloiI-an'd extraneous matter working up'into'the evaporator l4.

In the two-temperature ormulti-stage refrigcrating system'contemplated herein, the separate chambers A'and'B are maintained at different temperatures, and the flow of the refrigerant is effected through the instrumentality of a single rotary compressor having a double suction ar- ..ran'gement whereby both the high-pressure and '.lowg pressure refrigerant .from the. a respective through for said refrigerant, said first evaporator being adaptable to vaporize a portion of said refrigerant received by it, vapor conduit means connected between said first evaporator and said compressor whereby said vaporized portion of said refrigerant will be conveyed from said first evaporator to said compressor, check valve means interposed in said last mentioned conduit means adaptable to prevent oil or extraneous matter from working up into said first evaporator, refrigerant conduit means connected between said first evaporator and said second evaporator adaptable to convey to said second evaporator the remaining liquid refrigerant in said first evaporator, said last mentioned refrigerant conduit means including restrictor means having a relatively small cross-section therethrough for said refrigerant,

said second evaporator being adaptable tovaporize said liquid ref'rigera'nt received by it, vapor conduit means connected between said second evaporator and said compressor whereby said vaporized refrigerant in said second evaporator will be conveyed'to said compressor, and check valve means interposed in said last mentionedv conduit means adaptable to reduce reexpansion' volume of the refrigerant to a minimum.

2. A two temperature refrigerating system comprising, in combination, a compressor, a condenser into which compressed refrigerant is discharged from said compressor, a first evaporator, a second evaporator, a refrigerant restrictor means connected-to and disposed between said condenser and saidfirst evaporator, refrigerant return conduit means connected between said first evaporator andsaid compressor whereby a portionof 'said'refriger'ant will be conveyed from said first evaporator'to'said compressor, refrigera'nt conduit mans'connected-between said first evaporator and said second evaporator adaptable to convey to said'second evaporator any remaining liquid'refrigerantin' said'first evaporator and including refrigerant restrictor means having .a relatively small cross-section therethrough for said refrigerant, and refrigerant return conduit means connected between said second evaporator and said compressor whereby said vaporized refrigerant in said second evaporator will be .conveyed to said compressor.

3. A refrigerating system comprising, in combination, a compressor, a condenser into which compressed refrigerant is discharged from said compressor, a first evaporator and a second evaporator in series relationship, refrigerant restrictor means connected between said condenser and said first evaporator, said first evaporator being adaptable to vaporize a portion of said refrigerant received by it, vapor return conduit means connected between said first evaporator and said compressor and having check valve means interposed in said conduit means adaptable to prevent oil or extraneous matter from working up into said first evaporator, said second: evaporator being adaptable to vaporize said liquid refrigerant received by it, and vapor return conduit means connected between said second evaporator temperature evaporator and having a passage of relatively small cross-section therethrough for said refrigerant, said high temperature evaporator being adaptable to vaporize a portion of said refrigerant received by it, vapor conduit means connected between said high temperature evaporator and said compressor whereby said vaporized portion of said refrigerant will be conveyed from said high temperature evaporator to said compressor, check valve means interposed in said last mentioned conduit means adaptable to prevent oil or extraneous matter from working up into said high temperature evaporator, refrigerant conduit means connected between said high temperature evaporator and said low temperature evaporator adaptable toconvey to said low temperature evaporator the remaining liquid refrigerant in said high temperature evaporator, said last mentioned refrigerant conduit means including restrictor means having a relatively small cross-section therethrough for said refrigerant, said low temperature evaporator being adaptable to vaporize said liquid refrigerant received by it, vapor conduit means connected between said low temperature evaporator and said compressor whereby said vaporized refrigerant in said low temperature evaporator will be conveyed to said compressor, and check valve means interposed in said last mentioned conduit means adaptable to reduce re-expansion volume of the refrigerant to a minimum.

5. A refrigerating system comprising, incombination, a compressor, a condenser into which compressed refrigerant is discharged from said compressor, a first evaporator and a second evaporator in series-relationship, refrigerant restrictor means connected to said condenser and said first evaporator and having a passage of relatively small cross-section therethrough for said refrigerant, said first evaporator being adaptable to vaporize a portion of said refrigerant received by it, vapor conduit means connected between said first evaporator and said compressor. whereby said vaporized portion of said refrigerant will be conveyed from said first evaporator to said compressor and having check valve means interposed in said conduit means adaptable to prevent oil or extraneous matter from working up into said first evaporator. said second evaporator being adaptable to vaporize said liquid refrigerant received by it, vapor conduit means connected between said second evaporator and said compressor whereby said vaporized refrigerant in said second evaporator will be conveyed to said compressor and having check valve means interposed in said conduit means adaptable to reduce re-expansion volume of the refrigerant to a minimum.

6. In a two-temperature refrigerating system comprising a compressor, a condenser into which compressed refrigerant is discharged from said compressor, and a first evaporator and a second evaporator in series relationship, the combination of a refrigerant restrictor means connected to and disposed between said condenser and said first evaporator and comprising a member having a passage of relatively small cross-section therethrough for said refrigerant, of vapor return conduit means connected between said first evaporator and said compressor whereby vaporized portions of said refrigerant will be conveyed from said first evaporator to said compressor, of check valve means interposed in said last mentioned conduit means adaptable to prevent oil or extraneous matter from working up into said first evaporator, of vapor return conduit means connected between saidsecond evaporator and said compressor whereby vaporized refrigerant in said second evaporator will be conveyed to said compressor, and of check valve means interposed in said last mentioned conduit means adaptable to reduce re-expansion volume of the refrigerant to a minimum.

EARL F. HUBACKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,090,417 Hull Aug. 17, 1937 2,128,020 Smilack Aug. 23, 1938 2,222,707 Fletcher Nov. 26, 1940 2,309,797 Stickel Feb. 2, 1943 

